[C:1]([NH:4][C:5]1[CH:6]=[C:7]([C:15]([O:17][CH3:18])=[O:16])[C:8](=[CH:13][CH:14]=1)[C:9]([O:11][CH3:12])=[O:10])(=[O:3])[CH3:2].[N+:19]([O-])([OH:21])=[O:20]>C(Cl)Cl>[C:1]([NH:4][C:5]1[CH:6]=[C:7]([C:15]([O:17][CH3:18])=[O:16])[C:8](=[CH:13][C:14]=1[N+:19]([O-:21])=[O:20])[C:9]([O:11][CH3:12])=[O:10])(=[O:3])[CH3:2]Dimethyl 4-acetamidophthalate (100.4 g, 0.400 mol) is added to fuming nitric acid (90%, 600 mL) at 0° C. to 5° C. When the addition is completed (0.5 hour), the mixture is stirred 2.5 hours at 0° C. to 10° C., combined with cold methylene chloride and shaken with crushed ice. The aqueous layer is separated and extracted further with methylene chloride. The combined organic layers are washed with ice water, sodium bicarbonate solution and cold water, dried (MgSO4) and concentrated in vacuo to give a solid residue. The residue is recrystallized twice from methanol to afford the title product I as orange-brown needles, mp 119°-120° C. The original mother liquor is concentrated in vacuo, and the residue is recrystallized several times from carbon tetrachloride to afford the title compound II as light yellow needles, mp 124°-125° C. The yield of compound I is 38.9 g (32.9%), and the yield of compound II is 33.1 g (28.1%).
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